Postdoc, paper, thesis…

It’s been a busy couple of months here, hence my disappearance from blogging for a little while. But I’m back! Here’s what I’ve been up to:

  • At the end of January, I accepted a postdoctoral position in Oslo with Hans Kristian Eriksen, to start in May this year. I’m currently working with Hans Kristian and others on extending the Commander CMB analysis code to localised signals (especially my old favourite, the Sunyaev-Zel’dovich effect), and will be continuing some of that work as part of an ERC project, “The anisotropic universe”. There’s a bunch of other stuff that I’ll be working on too, but I’ll save the details for another post.
  • Since the postdoc starts so soon, I’ve had to write and submit my thesis in what may or may not be record time. As a result, I’ve lost all of February to filling-in forms, thesis writing/editing and all that jazz, but as of Monday, that’s all done and dusted. I’ll be spending the next couple of months finishing off a project, getting a start on a couple of new ones, and travelling a bit.
  • I put out a neat little paper with Marc Kamionkowski at the start of February. During a brief visit to Johns Hopkins in October, I had a fun chat with Marc about some of the work I’ve been doing on detecting large-scale inhomogeneity with the kinematic SZ effect. In this paper, we applied some of the same ideas to the situation where a large-scale inhomogeneity could be biasing the measurement of the spatial curvature parameter, ΩK. Even small biases in ΩK could cause serious problems if they were left uncorrected for; a detection of non-zero spatial curvature with Planck could all but rule-out eternal inflation, for example (depending on the sign of ΩK that was measured). We suggested a few possible methods for distinguishing between a bias caused by an inhomogeneity and a genuine departure from flatness on superhorizon scales. As it turns out, the KSZ effect measured at small angular scales by ACT and SPT already places quite tight upper limits on the possible size of a biasing effect of this type.

So things are pretty exciting right now, I’d say!


About Phil Bull

I'm a theoretical cosmologist, currently working as a NASA NPP fellow at JPL/Caltech in Pasadena, CA. My research focuses on the effects of inhomogeneities on the evolution of the Universe and how we measure it. I'm also keen on stochastic processes, scientific computing, the philosophy of science, and open source stuff. View all posts by Phil Bull

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